Sierra 3500 4WD V8-6.6L DSL Turbo VIN 2 (2004)
![background image](/gmc/sierra_3500_4wd/v8-6.6l_dsl_turbo_vin_2/Page-3514003.png)
Steps 4-7
The numbers below refer to the step numbers on the diagnostic table.
2. Lack of communication may be due to a partial malfunction of the class 2 serial data circuit. The specified procedure will determine the particular
condition.
4. The Symptom Table will determine the correct diagnostic procedure to use.
5. The presence of DTCs which begin with "U" indicate some other module is not communicating. The specified procedure will compile all the
available information before tests are performed.